IRF-1 AND PROLACTIN IN T CELL ACTIVATION

多肽激素催乳素(PRL)对这两种疾病都有深远的影响 细胞在各种组织中的增殖和分化，但 它作为免疫调节剂的作用还没有得到很好的定义。PRL扮演的角色 作为一种新的T和B细胞细胞因子，一个潜在的重要作用是 由于观察到催乳素受体(PRL-R)是一种 属于细胞因子受体超家族，表达于细胞的免疫 这些细胞中的一些还合成和分泌 生物活性催乳素。这项建议的长期目标是 了解催乳素的免疫调节特性。作为一个模型系统 为了研究催乳素作为T细胞细胞因子的作用，我们用大鼠 NB2T淋巴瘤细胞需要PRL才能生长。PRL的主要目标 刺激NB2T细胞的是转录因子干扰素 调节因子1(IRF-1)。在T细胞中，催乳素刺激双相 IRF-1的表达，首先在G1期激活，然后在G1期再次表达/S 转换，其中它的表达与DNA合成和 随后的细胞增殖。我们最近的研究表明， 细胞因子信号分子的信号转导和激活因子 转录“或STAT与细胞周期调控的转录 含有视网膜母细胞瘤蛋白(Rb)的复合体作为可能的PRL信号转导 IRF-I启动子上的分子。我们的工作假设是PRL和 它的受体参与了G1激活的信号传递，以及 激活的T细胞的S时相进展。细胞因子和细胞周期 信号分子在IRF-I启动子上以双相方式激活 举止。我们进一步推测，转录因子IRF-1是一种 催乳素在T细胞不同时相中的核调节作用 周而复始。拟议中的研究旨在阐明细胞因子如何发出信号 转导可以与细胞周期控制信号整合，以 调节IRF-1的表达，以及IRF-1对T细胞的重要性 激活和增殖。建议进行以下研究：1)表征 IRF-1启动子在G1期与S期的双相PRL反应， 并阐明Stat和Rb蛋白如何参与这些反应。 启动子元件的突变分析与基因突变的研究 蛋白质！DNA相互作用将有助于识别顺式作用元件和 影响催乳素刺激IRF-1基因的重要因素； 2)研究IRF-1在T细胞中的功能和催乳素的作用。CD8+T细胞 来自代表不同阶段的胸腺细胞和脾细胞 将发展作为PRL的潜在目标进行分析 免疫调节。IRF-1靶基因也将通过差异克隆 显示聚合酶链式反应，作为了解PRL(一种细胞因子信号)和 IRF-1(一个细胞因子靶点)调节T细胞的激活和增殖。 这些研究代表了一个全面的分子、遗传、生化 和免疫学方法来定义细胞因子信号是如何 整合细胞周期信号调控IRF-1基因表达 T淋巴细胞。了解催乳素如何调节生物功能 应阐明PRL的免疫调节特性，以及 提供对神经内分泌-免疫系统相互作用的新见解。

The peptide hormone prolactin (PRL) exerts a profound effect on both cellular proliferation and differentiation in a variety of tissues, but its role as an immunomodulator has not been well-defined. That PRL plays a potentially important role as a novel T and B cell cytokine has been strengthened by the observations that the PRL receptor (PRL-R), a member of the cytokine receptor superfamily, is expressed on cells of the immune system, and that some of these cells also synthesize and secrete biologically-active PRL. The long-term objective of this proposal is to understand the immunoregulatory properties of PRL. As a model system for investigating the role of PRL as a T cell cytokine, we are using the rat Nb2 T lymphoma cells which require PRL for growth. A major target of PRL stimulation in Nb2 T cells is the transcription factor, interferon regulatory factor-1 (IRF-1). In T cells, PRL stimulates the biphasic expression of IRF-1, first during G1 activation, and again over G1/S transition, where its expression is tightly linked to DNA synthesis and subsequent cell proliferation. Our recent studies have implicated the cytokine signaling molecules "signal transducer and activator of transcription" or Stat, and the cell cycle-regulated transcription complex containing retinoblastoma protein (Rb) as possible PRL signaling molecules at the IRF-i promoter. Our working hypothesis is that PRL and its receptors are involved in signaling for G1 activation as well as for S phase progression in activated T cells. Both cytokine and cell cycle signaling molecules are activated at the IRF-I promoter in a biphasic manner. We further suggest that the transcription factor IRF-1 is a nuclear mediator of PRL action during these distinct phases of the T cell cycle. The proposed studies aim to elucidate how cytokine signal transduction may be integrated with cell cycle control signals to regulate IRF-1 expression, and how IRF-1 may be important for T cell activation and proliferation. Studies are proposed to: 1) Characterize the biphasic PRL response at the IRF-1 promoter during G1 versus S phase, and to elucidate how Stat and Rb proteins participate in these responses. Mutational analysis of promoter elements coupled with studies of protein!DNA interactions will help to identify cis-acting elements and the transacting factors important for PRL stimulation of the IRF-1 gene; and 2) Investigate IRF-1 function and PRL action in T cells. CD8+ T cells from thymocytes and splenocytes representing different stages of development will be analyzed as potential targets of PRL immunomodulation. IRF-1 target genes will also be cloned by differential display PCR, as one way of understanding how PRL (a cytokine signal) and IRF-1 (one cytokine target) modulate T cell activation and proliferation. These studies represent a comprehensive molecular, genetic, biochemical and immunological approach to defining how cytokine signals are integrated with cell cycle signals to regulate IRF-1 gene expression in T lymphocytes. Understanding how PRL modulates the biological functions of T cells should elucidate the immunoregulatory properties of PRL, and provide new insights into neuroendocrine-immune system interactions.